Some sensitivity reactions to sulfites include itching and hives, vomiting, diarrhea, and upset stomach, as listed by WebMD. Other patients experience difficulty swallowing, breathing issues, dizziness, drops in blood pressure and flushing.
A small but significant percentage of people who are asthmatic are also allergic to sulfites, according to WebMD. This presents a significant danger because the already compromised airways in an asthmatic person can close up completely following exposure to sulfites if the individual also has a sulfite allergy. Because of this, 5 to 10 percent of people die following sulfite exposure if they also suffer from asthma.
Sulfites are in many foods, drugs and other substances, as WebMD details. Sulfur dioxide, sodium sulfite, sodium bisulfite, sodium metabisulfite and potassium bisulfite are all considered sulfites, and people with sulfite allergies need to avoid them. This is also true of potassium metabisulfite.
As of 2015, no one knows why sulfites cause adverse reactions in certain people, according to About.com. Not everyone who is allergic to sulfites produces antibodies against them. Some experts believe that the gases from sulfites affect the lungs of asthmatics and that some people's systems simply can't metabolize sulfites. About.com recommends that people with sulfite allergies avoid dried fruits except for prunes and dark raisins, non-frozen bottled lime and lemon juice, wine, molasses, sauerkraut, and grape juices.